a) Field of the Invention
The present invention relates to refrigerating production. Particularly, it applies to the liquefaction of the gases found in air and to apparatuses for the distillation of air. It is first concerned with a process for refrigerating production by expansion of a fluid in a first turbine called high pressure turbine followed by expansion of a portion of the fluid originating from this turbine in a second turbine called low pressure turbine.
b) Description of the Prior Art
In the known processes of this type, the high pressure turbine is the "hot" turbine, i.e. its inlet temperature is higher than that of the low pressure turbine. Such an arrangement has some disadvantages:
the fact of limiting the cooling of the total incoming air to the inlet temperature of the hot turbine is unfavourable to heat exchange;
the "cold" turbine treats a reduced flow of fluid, while it produces less cold per unit of flow of fluid and it is indeed in the cold zone that the most important quantity of cold is required when a gas has to be liquefied; however, it is also in this cold zone that heat losses are the most important.